Today (Monday) 3 people were detained and stopped and searched under Section 44 of the Terrorism Act 2000. This took place near Excel, London Docklands, where the DSEi arms fair is to be held next week. According to the cops (from the Forward Intelligence Team) they are able to do this in the whole Met Police District (ie the whole of London except the city) for the next month.
So if you are around in that area or going anywhere else where you might come across cops who think you look like a protestor (or anywhere that FIT team cops might be) don't carry anything dodgy and think about if you want to have ID on you (cos you don't have to give any details when stopped and searched).
The Terrorism Act 2000 can be found here: http://www.hmso.gov.uk/acts/acts2000/20000011.htm#aofs